Process of and apparatus for cooling ray tube anodes



C. L. GEBAUER Oct. 19, 1937.

PROCESS OF AND APPARATUS FOR COOLING RAY TUBE ANODES Filed March 5, 1937 INVENT OR.

BY CAar/ L. Gea ue ATTORNEY.

Patented Oct. 19, ,1937

UNITED STATES RATENT ()FFIQE Charles L. Gebauer, Cleveland, Ohio, assignor to The Gebauer Chemical Company, Cleveland, Ohio, a corporation of Ohio Application March 5, 1937, Serial No. 129,234

3 Claims.

This invention relates to cooling of ray tube anodes.

In apparatus for the production of special rays wherein cathode rays are caused to impinge upon an anode, great difficulty has been experienced in preventing loss of efficiency, lowering of capacity or impairment of the anode itself by reason of the intense heat to which the focal or active .point or target is subjected. Special heat resistant metals have been employed for the target and cooling water has been circulated in contact with the back of the active anode portion or target. Notwithstanding these expedients, the problem of overheating remains and constitutes a limiting factor in the operation of these devices. Accordingly, it is an object of the invention to provide an improved method of cooling the anodes of X-ray and like tubes.

A further object is the production of a tube of a construction well suited to the carrying out of the process. Other and more limited objects will be in part apparent and in part pointed out hereinafter in connection with the accompanying drawing wherein Fig. 1 is a diagrammatic view of a tube suitable for the performance of the process; Fig. 2 is an enlarged fragmentary longitudinal section through the anode end of the tube of Fig. 1; Fig. 3 is a section on the line 33 of Fig. 2; Fig. 4 is an end elevation looking from right to left in Fig. 2 and Fig. 5 is a fragmentary section similar to Fig. 2 but omitting the feeding device and showing cooling by the use of liquid air or similar liquid substance.

The tube shown in Fig. 1 may be of any suitable conventional construction with the exception of the anode portion and may comprise a cathode A including a filament not shown supplied with current from contacts B and C to one of which the active portion of the cathode may also be connected. Projecting into the other end of the glass tube D is an anode indicated generally by the reference character E and projecting outwardly beyond the glass tube and carrying a bus bar or conductor F. The glass tube D may be turned inwardly on itself, as indicated at H) and sealed to a ring H of platinum or similar metal having a coefficient of expansion suitable for scaling to the glass.

Sealed to the ring II is an outer metallic shell l2 which is sealed as indicated at l3 to an inner metallic shell M. It is to be understood that these shells may be integral or Welded or otherwise secured together. The inner shell I 4 has a closed inner end 15 disposed at a suitable angle and, if desired, carrying a special target inset [6 of special metal, such as tungsten. The shells l2 and it may be composed of copper or other suitable metal. The outer end of the inner shell I 4 is left open and unobstructed and the elec-- trical contact may be taken off therefrom by means of a bus bar l'i including a band l8 surrounding and secured to the shell M, as indicated at ill, by solder, welding or equivalent electrical connection. A cap member 20 which may be composed of rubber or any suitable material is frictionally or otherwise detachably applied thereto. The cap member 28 is provided with openings 2! for the escape of gas and has an inwardly extending boss 22 carrying a spring 23 adapted to engage a stick 24 of cooling substance whereby to feed the same against the back of the target portion as it is consumed. The stick 24 may be composed of solid carbon dioxide or similar substance which is gaseous at room temperature (70 F.) and which therefore may absorb great quantities of heat in being converted into a gas which may escape: outwardly through the inner shell l4 and through the openings 2| into the surrounding atmosphere. While I prefer to use solid carbon dioxide, it is to be understood that other materials of similar properties may be used.

In Fig. 5, I have shown substantially the same construction arranged in vertical position and omitting the cap 20 and following spring 23. In this case, I may maintain in the anode and. in

contact with the back of the target a suitable quantity of liquid air or similar liquid cooling material 25. This material may be introduced in any suitable manner but preferably in rather small quantities, being constantly renewed as it is converted into gas.

In order to avoid subjecting the glass-metal seal 26 to extreme differences of temperature at the two sides thereof, I prefer to connect the outer shell I? to the inner shell M at a point adjacent the inner end of the latter whereby such glassmetal joint is to some extent isolated from the low temperature material. A ring of cement 21 of low heat conducting properties interposed between the inner shell I l and the inturned p0rtion ID of the glass tube D forms a dead air space between the shells and also forms a mechanical support between the glass tube and the inner shell member.

While I have disclosed present preferred modes of realizing my invention, I am aware that the same may be practiced in different Ways, and by 7 apparatus other than that disclosed and I therefore do not wish to be limited except in accordance with the appended claims.

Having thus described my invention, what I claim is:

1. Method of cooling ray tube anodes of the type which comprises a shell the exterior of which is presented to the inside of the tube and the interior of which is accessible from the outside of the tube, comprising maintaining within the shell and in substantial contact with the back of the active anode or target portion thereof a cold substance in a solid state such substance having the characteristic of becoming gaseous at a temperature not substantially higher than minus '7 9 C.

2. Method of cooling ray tube anodes of the type which comprises a shell the exterior of which is presented to the inside of the tube and the interior of Which is accessible from the outside of the tube, comprising maintaining Within the shell and in substantial contact with the back of the active anode or target portion thereof a body of solid carbon dioxide.

3. A ray tube including an anode comprising an outer metallic shell having its outer end sealed to the tube, an inner metallic shell sealed to said outer shell and having a closed inner end forming the active anode portion or target of the tube and having its outer end unobstructed whereby a stick of solid cooling substance may be introduced into contact with the back of said target, and means for feeding such stick into contact with said target as such stick is consumed.

CHARLES L. GEBAUER. 

